University of Virginia Health System

Prolymphocytic B Cell Leukemia
(B-PLL)

 
Prolymphocytic B cell leukemia (B-PLL)- Peripheral blood smear, Wright-Giemsa stain, 1000x

Description:

When compared to small B-CLL cells, the cells are larger by 1½-2 times, and have more abundant basophilic (blue) cytoplasm. The nucleus usually is eccentrically located and may be round, oval or clefted, and the nuclear chromatin is immature, but frequently clumped, and prominent nucleoli are usually visible. Cannot differentiate from T-PLL by morphology.

Immunophenotype:

Clonal cells are CD19+, FMC7+, CD5- (CD5 dimly positive in approximately 30% of cases), CD23-, CD11c-, CD103-, and CD10-.

Cytogenetics:

No signature cytogenetic abnormality has been identified. Deletions frequently seen in small B-CLL may be present, especially in those cases transformed from B-CLL. The mantle cell signature cytogenetic abnormality, t(11;14) is reported to be present in up to 30% of cases, and is thought to represent blastic variants of mantle cell leukemia- the morphologic features on a Wright-Giemsa stain are very similar.

Clinical and Laboratory Manifestations:

The typical de novo case presents with splenomegaly, often massive, absence of lymphadenopathy, marked lymphocytosis (≥100,000/mm³,) and at a slightly older age compared to B-CLL, and cytopenias usually are more pronounced. In those cases that have transformed from B-CLL, defined as 50% or more prolymphocytes on a differential lymphocyte count, the prognostic significance is not as predictable as in de novo cases.

Prognosis:

Poor. Response to agents that are effective in B-CLL is generally very poor. Best results are seen with the use of the humanized anti-CD52 monoclonal antibody (alemtuzumab, Campath-1H.) Splenectomy, particularly in those with massive splenomegaly, often results in resolution of cytopenias and manifestations due to the massive splenomegaly (e.g. hypermetabolism, early satiety, weight loss.)

General References:

• Jaffe ES, Harris NL, Stein H, Vardiman JW, eds. Pathology and genetics of tumours of hematopoietic and lymphoid tissues. Vol. 3 of World Health Organization classification of tumors, Lyon, France: IARC Press, 2001
• Melo JV, Vatovsky D, Galton DA. The relationships between chronic lymphocytic leukemia and prolymphocytic leukemia. I. Clinical and laboratory features of 300 patients and characterization of an intermediate group. Br J Haematol 63:377, 1986

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